WO2009156514A1

WO2009156514A1 - Tripod joint for a motor vehicle and method for the production thereof

Info

Publication number: WO2009156514A1
Application number: PCT/EP2009/058072
Authority: WO
Inventors: Luis Hoeks; Jessica Andresen; Christian Felchner
Original assignee: Tedrive Holding B.V.
Priority date: 2008-06-27
Filing date: 2009-06-26
Publication date: 2009-12-30
Also published as: DE102008030116A1

Abstract

The invention relates to a tripod joint for a motor vehicle having improved rolling characteristics. The joint comprises a tripod star (40) forming a plurality of journals (42). The journals (42) of the tripod star (40) bear a plurality of rolling bearings (60). Furthermore, an outside joint (20) is provided, which has a plurality of raceway recesses (22) extending in the axial direction, in each of which a rolling bearing (60) carried by a journal (42) is supported displaceably in the axial direction. Two raceways (24) disposed opposite each other are designed in each raceway recess (22) for mechanical contact with the rolling bearing (60) guided therein. The invention further relates to a method for producing a tripod joint having improved rolling characteristics.

Description

Designation: Tripod joint for a motor vehicle and method for its production

The present invention is a tripod joint for a motor vehicle according to the preamble of claim 1 and a method for its preparation according to the preamble of the claim.

Automotive tripod joints have long been known in the art, and are particularly used as inner joints for the drive shafts of front wheel drive motor vehicles. They have excellent synchronous characteristics and can be angled up to angles of typically over 10 °. In addition, tripod joints can be advantageously used for propshafts rear-wheel drive or four-wheel drive motor vehicles.

Tripod joints typically have a tripod star forming a plurality of pins, each pin carrying a rolling bearing. Furthermore, a tripod joint comprises an outer joint, which is often referred to as a "tulip", wherein the outer joint has a plurality of in the axial direction (ie in the direction of rotation of the outer joint) extending Laufbahnausnehmungen.In each Laufbahnausnehmung a bearing supported by a pin roller bearing in the axial direction is displaceable Each raceway recess forms two oppositely arranged raceways for mechanical contact with the rolling bearing guided therein.

Although the basic construction of the tripod joints, which are also known as "homokinetic joints", has long been known, nevertheless great efforts are still being made to improve the running properties of tripod joints, for example during load change processes DE 41 30 183 A1 a tripod joint, in which by a special design of the raceways in the Laufbahnausnehmungen and the outer rings of the bearings tilting of the rolling bearing outer ring in the Laufbahnausnehmung eg at a load application or a load change is to be prevented only comes to rest on on a track of the raceway recess, so that the outer ring can roll friction in the Laufbahnausnehmung. Also EP 1 253 337 A1 discloses a homokinetic joint with reduced rotational play. Both the raceways of the Laufbahnausnehmungen and the surface of the rolling bearing outer ring are designed spherical. Furthermore, the rolling bearing outer ring is divided into two parts.

Both Tripodegelenken is a relatively complex configuration of the bearings together, which brings cost disadvantages.

Object of the present invention is therefore to provide a tripod joint with advantageous operating characteristics, in particular with minimal rotational clearance, which has a simplified structure. Furthermore, a method for producing an advantageous tripod joint is to be specified.

This object is achieved by a tripod joint with the features of claim 1 and a method having the features of claim 17.

An inventive tripod joint is provided for the drive train of a motor vehicle. In particular, it is suitable for use as an inner joint of a drive shaft of a front wheel drive motor vehicle. It includes a tripod star, which forms a plurality of cones. Each of the pins carries a rolling bearing. The tripod joint further comprises an outer joint, which has a plurality of in the axial direction (ie in the direction of rotation of the outer joint of the tripod joint) extending raceway recesses. In each Laufbahnausnehmung a supported by a pin bearing is mounted displaceably in the axial direction. Furthermore, two oppositely arranged raceways for mechanical contact with the rolling bearing guided therein are formed in each raceway recess. When a load is introduced into the outer joint, it is transmitted to the tripod esters via the roller bearings and the pins carrying them.

According to the invention, the rolling bearings each have an outer ring, in whose outer peripheral surface at least one, but preferably two circumferential annular grooves are formed. The outer ring is advantageously formed in one piece, but may also be designed in several parts, in particular in two parts. Furthermore, in the raceways of the outer joint at least one rail-like Führungsele- formed, but preferably two guide elements, which / engages in the annular ring / s formed on the outer ring / s. Here, a rail-like guide element is to be understood as a structure which extends in the direction of the axis of rotation D of the outer joint and rises from a track. It may, for example, rise substantially in the circumferential direction of the outer joint of the raceway. Furthermore, the rail-like guide element should form at least one guide surface on which the outer ring of a roller bearing can roll. However, the rail-like guide element preferably forms two guide surfaces, which are arranged on sides of the guide element facing away from one another.

In particular, the annular groove in the outer ring of the rolling bearing and the rail-like guide element in the raceways should be designed so that at a power transfer from the outer joint on the tripod of the outer ring of the roller bearings on each / the rail-like guide / s - in particular / the guide surfaces formed by this rolls. This is intended to ensure that a mechanical contact between roller bearing outer ring and raceway recess forms essentially only in the region of a raceway when the load transfer is effected via the tripod joint according to the invention. On the other hand, a mechanical contact of the roller bearing outer ring in the region of the second, oppositely arranged track should be avoided as far as possible due to the special shape of the outer ring outer circumferential surfaces and the rail-like guide elements. In this way, particularly advantageous rolling properties of the roller bearings in the raceway recesses and thus particularly good synchronous running properties of the tripod joint according to the invention can be realized.

In a particularly preferred embodiment, at least two, but preferably three or more point contacts between the outer peripheral surface of the outer rings of the rolling bearings and the raceways, d, when rolling a rolling bearing in a load transfer in the tripod joint according to the invention. H. the rail-like guide elements, in the outer joints.

In a further advantageous embodiment, at least one of the rail-like guide elements at least in sections a kreisbogenförmi- on cross-section. Furthermore, the associated annular groove, in which engages the aforementioned rail-like guide element with at least partially circular arc-shaped cross-section, also at least partially on a circular arc-shaped cross-section. In this case, the radius of curvature of the arcuate portion of the rail-like guide element is preferably smaller than that of the associated annular groove in the outer ring of the rolling bearing. In this embodiment, in particular, the Hertzian contact voltages are minimized.

Alternatively, it is also possible that that annular groove in the outer peripheral surface of the roller bearing outer ring, in which engages the aforementioned rail-like guide element, at least partially has a Gothic cross-section. This is understood to mean two mutually inclined spherical surface sections which enclose an angle α with each other. The combination of annular groove with at least partially Gothic cross section and rail-like guide element with at least partially circular arc-shaped cross-section ensures that always form two defined point contacts P between rail-like guide element and annular groove.

In an advantageous embodiment of the tripod joint according to the invention at least one rail-like guide element is formed integrally with the tulip, it can be formed for example in the manufacture of the outer joint with in the material of the outer joint. In particular, the final formation of the rail-like guide element can be carried out in the context of the finishing of the raceways in the outer joint.

In a preferred alternative embodiment, the rail-like guide element is designed as a separate component. In particular, it may consist of a different material than the outer joint of the tripod joint. For example, the rail-like guide element may consist of an extruded tool steel or a hardened round steel. The outer joint is typically cast or forged steel. In this case, the separately formed rail-like guide element is advantageously fixed mechanically to the tulip at at least one point, but preferably at several points. The mechanical connection between the rail-like guide element and the outer joint can be achieved, for example, by means of welding (for example by welding). Spot welding), caulking, soldering, gluing or other suitable joining methods known from the prior art.

Basically, the Tripodegelenk each known from the prior art suitable shaping with respect. The pins of the tripod star or the inner rings of the rolling bearing have. In a particularly preferred embodiment, the pins of the tripod star are formed spherical, which is to be understood in that the pins are at least partially form spherical surfaces. The complementary surfaces in the inner ring of the rolling bearing can be configured, for example, cylindrical, so that the rolling bearing has an inner ring with a cylindrical inner recess. Alternatively, it is also possible to provide the inner rings of the rolling bearing with an inner recess, the shape of which in turn is formed at least partially spherical surface. In both embodiments, the inner rings can perform a tilting movement on the pin of the Tripodesterns. In the latter embodiment, it is of particular advantage if the inner ring and the outer ring of the rolling bearing in the direction of the axis of rotation of the bearing are mutually displaceable. Such a degree of freedom of movement, on the other hand, is not required if the inner ring of the roller bearing has a cylindrical inner recess, since here the spherical pin of the tripod stator can slide back and forth in the inner recess of the roller bearing inner ring.

An inventive method for producing a tripod joint for a motor vehicle comprises the following method steps: 1. Provision of a. a tripod star forming a plurality of pins, b. a plurality of roller bearings, each having an outer ring, in the outer peripheral surface of which at least one circumferential annular groove is formed, c. an outer joint having a plurality of axially extending raceway recesses, in each of which a rolling bearing supported by a pin can be slidably supported in the axial direction, wherein in each Laufbahnaus- recess formed two oppositely arranged raceways for mechanical contact with the roller bearing guided therein and at least one rail-like is formed, which engages in the annular groove formed on the outer ring,

2. placing the bearings on the pins of the tripod esters, and

3. Introduce the bearings in the Laufbahnausnehmungen.

In a preferred development, the method according to the invention has the following additional method steps:

4. Provision of a plurality formed as a separate component rail-like guide elements, and

5. Determining the rail-like guide elements on the outer joint.

Further advantages and features of the inventive Tripodege- lenk result from the subclaims and the embodiment, which is explained in more detail in the appendix of the drawing. In this show:

1 is a perspective view of a first embodiment of a tripod joint according to the invention,

2 shows a partial sectional view of the tripod joint of Figure 1,

3 shows an enlarged partial sectional view through the outer joint, roller bearings and tripod testers of the exemplary embodiment according to FIG. 1.

4 shows a perspective partial sectional view of the tripod joint

FIG. 1

5 is a perspective view of the outer joint of a tripod joint according to a second embodiment with a rolling bearing used,

6 is an enlarged partial view of Figure 5,

7 shows the view from FIG. 4 for a third exemplary embodiment of a tripod joint according to the invention, 8 is an enlarged partial view of Figure 7 in a first embodiment, and

9 shows an enlarged partial view from FIG. 7 in a second embodiment.

Figure 1 shows a schematic representation of a first embodiment of a tripod joint 1 according to the invention in a perspective view. The outer joint 20 has a rotation axis D and is open on one side. At its closed end, the outer joint 20 opens into a shaft shank 28 for connection to, for example, an output shaft of a transmission of the motor vehicle. In the outer joint 20 three Laufbahnausnehmungen 22 are formed, which extend in the direction of the axis of rotation D. Each raceway recess 22 forms two raceways 24 arranged opposite one another, on which roller bearings 60 inserted into the raceway recess 22 unroll, of which only one is shown in FIG. 1 for reasons of clarity. The dimensioning of the bearings 60 is selected so that when a force is introduced, for example, in the outer joint 20 of the tripod joint 1, the roller bearing 60 actually rolls with its outer ring 64 only on a raceway 24 of the raceway recess 22.

As is further apparent from FIG. 1, each raceway recess 22 in the outer joint 20 is assigned a pin 42 of the tripod stator 40 inserted into the outer joint 20. The pins 42 each carry a rolling bearing 60. The tripod star 40 has an inner recess, in the inner wall of a plurality of splines 44 are formed for connecting a connecting shaft, for example, a ball displacement joint.

Preferably, the outer joint 20 and shaft shaft 28 are integrally formed as a forged part, wherein the formed in the Laufbahnausnehmungen 22 raceways 24 are subjected to the forging of the outer joint 20 further processing steps for finishing and curing.

FIG. 2 shows the first exemplary embodiment of a tripod joint 1 according to the invention according to FIG. 1 once more in a partially sectioned view from which the structure of the roller bearing 60, in particular of its outer ring 64, and the shape of the raceway 24 of the raceway recess 22 in the outer joint 20 can be seen. The supported by the pins 42 of the tripod stator 40 bearings 60 have an inner ring 62 and an outer ring 64, between which a plurality of cylindrical rollers 68 is arranged. Inner ring 62 and outer ring 64 are displaceable relative to each other in the direction of the axis of rotation R of the rolling bearing 60. As is apparent from the sectional view of the rolling bearing 60 in Figure 2, the outer ring 64 of the rolling bearing 60 is provided with a circumferential annular groove 66. In this engages a rail-like guide member 26, which is formed in each case on the raceway 24 of the raceway recess 22. In this case, this rail-like guide member 26 may be integrally formed with the outer joint 20, but it may also be formed as a separate component, for example in the form of an insert which each inserted into a trained in the raceway 24 of the Laufbahnausnehmung 22 receiving recess 25 and preferably mechanically fixed there In the exemplary embodiment shown in FIGS. 1 and 2, the rail-like guide element 26 is formed integrally with the forged outer joint 20.

As can also be seen from FIG. 2, the pins 42 of the tripod star 40 have spherical surface sections 43. At the same time, the inner recess 62 of the inner ring 62 is formed partially spherical, so that the pin 42 supported by the inner ring 62 of the rolling bearing 60 and thus this total can perform a tilting movement about the pin 42.

In the first exemplary embodiment according to FIGS. 1 to 4, only one rail-like guide element 26 is formed in the raceways 24 of the raceway recess 22 in the outer joint 20, as can be seen again in detail from FIG. At the same time only a circumferential annular groove 66 is formed in the outer ring 64 of the rolling bearing 60, in which the rail-like guide member 26 engages. Due to the special shape of the raceway 24 and the outer peripheral surface of the outer ring 64 of the rolling bearing 60 arise when rolling the roller bearing 60 on the track 24 mech. Contacts only between the outer ring 64 and the raceway 24. These are marked in Figure 3 with P. All three contact points P lie on the rail-like guide element 26 and have the same distance from the axis of rotation R of the rolling bearing 60, so that a pure rolling movement of the rolling bearing 60 on the track 24 is possible. A partial sliding movement of the outer ring 64, which could adversely affect the running properties of the tripod joint 1 according to the invention, is characterized avoided. The realized in the first embodiment of the invention Tripode joint 1 three contact points P of the rolling bearing outer ring 64 with the raceway 24 also provide a position stabilization of the rolling bearing outer ring 64 in the track 24, for example, at a load transfer to the invention Tripodege- steering 1, ie a tilting of the axis of rotation R. the rolling bearing 60 is thereby avoided. In this way it can be ensured that even with a load introduction into the tripod joint 1, a mechanical contact between the roller bearing 60 and a raceway recess 22 takes place only in the region of a raceway 24. A sliding application of the roller bearing outer ring 66 on the opposite raceway 24 can be safely avoided thereby. The sliding movement of the outer ring of the rolling bearing on the track facing away from the force path in many prior art tripod joints occurring in many of the prior art is therefore eliminated in this construction.

FIG. 3 furthermore shows the special shape of the roller bearing 60 and the pin 42 of the tripod star 40. In particular, the spherical surface portion 43 of the pin 42 of the tripod star 40 can be seen. With this, the spherical inner recess 63 in the inner ring 62 of the rolling bearing 60 corresponds, so that a total of a tilting movement of the axis of rotation of the rolling bearing 60 on the pin 42 is possible. The outer circumference of the roller bearing inner ring 62 and the inner circumference of the roller bearing outer ring 64 are each configured as a cylindrical surface, so that between the inner ring 62 and outer ring 64 cylindrical rollers 68 can roll. The rollers 68 are fixed in the direction of the axis of rotation R of the rolling bearing 60 in the inner ring 62 in position. By contrast, the position of the outer ring 64 on the rollers 68 is limited essentially only by a securing projection 65 which is formed at the inner end of the roller bearing outer ring 64. As a result, the roller bearing outer ring 64 is displaceable in the direction of the axis of rotation R of the rolling bearing 60 against the inner ring 62. The securing projection 65 limits the displacement movement of the outer ring 64 on the inner ring 62 and thus prevents falling apart of the supported by the pin 42 rolling bearing 60, for example, in the final assembly of the tripod joint 1 of the invention.

Figure 4 shows again the structure of the outer joint 20, the tripod star 40 and the rolling bearing 60 of the tripod joint 1 according to the invention according to the first embodiment in a perspective view. Figure 5 shows the outer joint 20 of a second embodiment of a tripod joint 1 according to the invention also in a perspective view, which was omitted for the sake of clarity, the Trip odestern 40 again in detail. In this embodiment, the structure of the tripod stator 40 and the rolling bearings 60 substantially corresponds to that according to the first embodiment. The second exemplary embodiment differs from the first exemplary embodiment essentially in that two circumferential annular grooves 66 are formed on the outer circumferential surface of the roller bearing outer ring 64. At the same time two rail-like guide elements 26 are formed on the track 24 in the Laufbahnausnehmungen 22 of the outer joint 20, each forming two guide surfaces and engage in the two circumferential annular grooves 66 in the rolling bearing outer ring 64. This is again clear from the enlarged detail according to FIG. 6, from which the rail-like guide elements 26 in the raceway 24 of the raceway recess 22 of the outer joint 20 can be seen. Also, the complementary circumferential annular grooves 66 in the outer ring 64 of the rolling bearing 60 can be seen. In the second embodiment according to Figures 5 and 6, the rail-like guide elements 26 are integrally formed with the outer joint 20, for example, forged.

This differs from the embodiment according to FIG. 7 in that the rail-like guide elements 26 are designed as separate components of the outer joint 20. These are placed in complementary, in the direction of rotation D of the outer joint 20 extending receiving recesses 25 in the raceway 24 and mechanically fixed there, for example by means of one or more welds. The rail-like guide elements 26 may consist, for example, of hardened round steel.

In the exemplary embodiments according to FIGS. 6 and 7, the rail-like guide elements 26 each partially have a circular arc-shaped cross section. Likewise, the circumferential annular grooves 66 formed in the roller bearing outer ring 64 have, in sections, a circular arc-shaped cross section. In this case, the radius of curvature of the arcuate portion of the rail-like guide element 26 is at most the same size as the radius of curvature of the circumferential annular groove 66 in the roller bearing outer ring 64, preferably but smaller than its radius of curvature. The latter embodiment is shown in Fig. 8 as an enlarged view of Figure 7. This results in a minimized Hertzian contact voltage at the contact points P between the rail-like guide element 26 and the annular groove 66. In the exemplary embodiments according to FIGS. 5 to 7, two contact points P are formed in the region of each circumferential annular groove 66, each with one rail-like element engaging in the annular groove 66 Guide member 26, so that a total of four between the rolling bearing outer ring 64 and the raceway 24 of the outer joint 20 four contact points P occur. In this case, these contact points P are preferably again on a straight line which is oriented parallel to the axis of rotation R of the rolling bearing 60. Provided that four contact points P are provided, a further stabilization of the roller bearing outer ring 64 against tilting, for example when force is introduced into the tripod joint 1, is prevented, so that a pure rolling movement of the rolling bearing outer ring 64 on a raceway 24 of a raceway recess 22 is ensured. This in turn leads to particularly advantageous running properties of the tripod joint 1 according to the invention.

In an alternative embodiment, which is shown in FIG. 9, the structure of the tripod joint 1 essentially corresponds to that shown in FIGS. 5 and 7. Here too, the rail-like guide elements 26 designed as separate components have, in sections, a circular-arc-shaped cross-section. On the other hand, the peripheral annular grooves 66 formed in the outer ring 64 of the roller bearing 60 do not have a sectionally circular-arc-shaped cross-section, but rather a Gothic shape is selected here for the annular grooves. As has already been explained, this is to be understood as two mutually inclined spherical surface sections, which enclose with one another an angle α which lies between 45 ° and 170 °, preferably between 90 ° and 150 °.

Claims

claims

1. Tripod joint (1) for a motor vehicle, with a. a tripod stator (40) forming a plurality of pins (42), b. a plurality of rolling bearings (60) carried by the pins (42) of the tripod star (40), c. an outer joint (20) having a plurality of axially extending Laufbahnausnehmungen (22), in each of which a pin (42) supported rolling bearing (60) is mounted displaceably in the axial direction, wherein in each Laufbahnausnehmung (22) two opposite arranged raceways (24) are designed for a mechanical contact with the rolling bearing (60) guided therein,

characterized in that

d. the roller bearings (60) each have an outer ring (64), in whose outer peripheral surface at least one circumferential annular groove (66) is formed, e. in the raceways (24) at least one rail-like guide element (26) is formed, which engages in the on the outer ring (64) formed annular groove (66).

2. tripod joint (1) according to claim 1, characterized in that when rolling a rolling bearing (60) on a raceway (24) at least two point contacts are formed.

3. Tripod joint (1) according to claim 1, characterized in that a. in the outer surface of the rolling bearing (60) has two circumferential annular grooves (66) are formed, and b. in the raceways (24), two rail-like guide elements are formed, which engage in the on the outer ring (64) formed annular grooves (66).

4. tripod joint (1) according to claim 1, characterized in that at least one rail-like guide element (26) at least partially has a circular arc-shaped cross-section.

5. tripod joint (1) according to claim 1, characterized in that at least one annular groove (66) at least partially has a circular arc-shaped cross-section.

6. tripod joint (1) according to claim 1, characterized in that at least one annular groove (66) at least partially has a Gothic cross-section.

7. tripod joint (1) according to claim 1, characterized in that at least one rail-like guide element (26) integral with the outer joint (20) is formed.

8. tripod joint (1) according to claim 1, characterized in that at least one rail-like guide element (26) is designed as a separate component.

9. tripod joint (1) according to claim 8, characterized in that the separately formed rail-like guide member made of a different material than the outer joint (20).

10. Tripod joint (1) according to claim 8, characterized in that the separately formed rail-like guide element consists of hardened round steel.

11. tripod joint (1) according to claim 8, characterized in that the separately formed rail-like guide element at at least one point mechanically fixed to the outer joint (20).

12. tripod joint (1) according to claim 11, characterized in that the mechanical connection of separately formed rail-like guide element by means of welding, caulking, soldering or Bonding is made.

13.Tripodegelenk (1) according to claim 1, characterized in that the pins (42) are formed spherical.

14.Tripodegelenk (1) according to claim 1, characterized in that the rolling bearings (60) have an inner ring (62) with a cylindrical inner recess.

15.Tripodegelenk (1) according to claim 1, characterized in that the rolling bearing (60) has an inner ring (62) with an inner recess whose shape is at least partially spherical surface.

16. A method for producing a tripod joint (1) for a motor vehicle, comprising the following method steps: a. Provide i. a tripod stator (40) forming a plurality of pins (42), ii. a plurality of roller bearings (60), each having an outer ring (64), in whose outer peripheral surface at least one circumferential annular groove (66) is formed iii. an outer joint (20) having a plurality of in the direction of the rotation axis D of the outer joint (20) extending Laufbahnausnehmungen (22), in each of which a pin (42) supported rolling bearing (60) can be mounted displaceably in the axial direction, wherein in each Laufbahnausnehmung (22) has two oppositely disposed raceways (24) for mechanical contact with the therein rolling bearing (60) are formed, and in the raceways (24) at least one rail-like guide element (26) is formed in the on Outer ring (64) formed annular groove (66) engages, b. Placing the roller bearings (60) on the pins (42) of the tripod star (40), c. Inserting the rolling bearings (60) in the Laufbahnausnehmungen (22).

17. The method according to claim 16, characterized in that the following further method steps are carried out: a. Providing a plurality of rail-like guide elements formed as a separate component, and b. Determining the rail-like guide elements on the outer joint (20).